Cummins/Onan — Troubleshoot - Coolant Loss

Testing & diagnosis · Cooling system

From a Cummins/Onan service manual — check it applies to your exact model before use.

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Procedure

1. Check coolant level
2. Check for cracked or leaking hoses
3. Check loose hose clamps
4. Check for coolant in oil
5. Pressure test cooling system (cold)
6. Pressure test cooling system (hot)

Source: Cummins/Onan service manual. Steps and values are as documented; always cross-check against the official manual and any later revisions for your exact serial number before servicing.

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